The prior application discloses a tamper evident closure for containers of potentially hazardous materials. The container closure is snap locked into engagement with the neck of the container body in a manner which allows free rotation of the closure in either direction. A cooperative tamper indicating means on the container body and closure including circumferentially spaced frangible parts is provided. At least one frangible part is destroyed during rotation of the closure relative to the container body toward a release position in either direction of rotation.
While the above arrangement in the prior patent application provides an excellent foolproof and simplified tamper indicator means for a child-resistant container and container closure, it has been found that it is sometimes possible to pry the closure cap from the container by using an implement, such as a knife blade, screwdriver or the like. In some cases, the prying operation can be accomplished without leaving any visual evidence, thus defeating the purpose of the invention.
Accordingly, it is the objective of the present invention to deal with the above drawback present in the prior device, and to deal with it completely and successfully in a simple and economical manner.
In accordance with the present invention, the closure cap pry off problem is solved by forming on the side wall of the closure cap a narrow 360.degree. tamper evident extension skirt which is received within a 360.degree. recess formed in the top of the container dust ring when the cap is placed on the container neck. Any prying device which could successfully separate the cap from the container will necessarily damage the extension skirt of the cap and/or recess sufficiently to render the same tamper evident, thus overcoming the difficulty of the prior art.
Other objects and advantages of the invention will become apparent during the course of the following detailed description.